What is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5?

Answer 1

Bromine.

Answer 2

Kr

Answer 3

It is rubidium. 1st group 5th period hence 5s1 at the back. count the number of electrons it has in its ground state and it adds up to 37 which is the proton number of rubidium.

Using exponents, the configuration reads :

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1

or [Kr] 5s1

Answer 4

that's the electron configuration of iron

But there is a 2p6 orbital missing. Just 20 electrons accounted for.

So correct electron configuration of iron would be 1s2 2s2 2p6 3s2 3p6 3d6 4s2. All 26 electrons accounted for.

Answer 5

This element has 2+2+6+2+6+2+10+6+2 = 38 electrons, thus it is element with atomic number 38, Strontium (Sr)

Answer 6

that is non-existant as all the "P" orbitals must be filled first (they have 6 electrons)

Answer 7

Krypton. (I ignored the lone 4 at the end of your question).

Answer 8

it is the electronic configuration of the elements

Answer 9

Calcium's electron configuration.

Answer 10

Arsenic